Sewing machine



June 3, 1969 sPlNRAD V 3,447,500

SEWING MACHINE Filed June 22, 1967 INVENTOR MALCOM SPINRAD BYMJQM ATTORNEY United States Patent 3,447,500 SEWING MACHINE Malcom Spinrad, Reading, Pa., assignor to American Safety Table, a Teledyne company, a corporation of Pennsylvania Filed June 22, 1967, Ser. No. 648,106 Int. Cl. Db 83/00; D05g 25/00; F04d 29/70 US. Cl. 112261 1 Claim ABSTRACT OF THE DISCLOSURE Drive mechanisms of sewing machines are partially enclosed within a protective pulley guard in the form of a rigid wire basket that permits the passage of air and prevents the accumulation of lint and other pieces of cloth debris.

This invention relates to industrial sewing machines and, more particularly, to improved pulley guards that enclose at least a portion of the drive mechanisms of such sewing machines.

Industrial sewing machines are generally of the type in which a sewing machine is mounted on the top of a work table and a drive mechanism is mounted on the underside of the work table. Power is transmitted from the drive mechanism to the sewing machine by means of a drive belt that extends through an opening in the work table to link a drive pulley on the drive mechanism with a driven pulley on the sewing machine. To protect the operator from inadvertently contacting the drive pulley or the drive belt, and to protect the drive pulley and the pulley belt from accidental fouling, it is conventional to provide a pulley guard or shield that generally surrounds the drive pulley and drive belt. These pulley guards may be mounted on the end member of the drive housing and are commonly provided with hinges to permit access to the drive pulley and drive belt for maintenance and repair. While it is of no particular consequence to the instant invention, it may be noted that the drive housing generally encloses both an electric motor and a clutch, and that, therefore, the terms drive housing and motor and clutch housing are used synonomously here- 1n.

Difiiculties have been encountered with the above described type of pulley guard due to the fact that particles of lint, stray pieces of cloth and other sewing debris will accumulate within the pulley guard. This accumulation of combustible materials constitutes a fire hazard due to the proximity of the accumulated scrap material to the electric motor.

Conventional pulley guards may also be disadvantageous in that they shield the end plate of the motor and clutch housing and inhibit the circulation of air and the dissipation of heat. This lack of air circulation is further reduced when sewing debris accumulates in the pulley housing, and in addition to intensifying the fire hazard, may cause damage to the motor and drive mechanism. As a result, it is necessary that these pulley guardsbe opened at frequent intervals and cleaned of the accumulated debris.

Also, conventional pulley guards may be cumbersome since they generally must be removed to effect routine adjustment, maintenance and repair of the drive mechanism including the pulley and pulley wheel.

Accordingly, it is an object of this invention to provide an improved pulley guard for enclosing the drive mechanism of electrical sewing machines.

Another object of this invention is to provide a pulley guard for use with sewing machines that will not accumulate dust and various sewing debris.

Yet another object of this invention is to provide a pulley guard that will not interfere with the circulation of air around the end member of a motor and clutch housing.

Still another object of this invention is to reduce fire hazard attendant upon the accumulation of dust and sewing debris within pulley guards.

Still a further object of this invention is to provide improved pulley guards that will facilitate the cleaning and servicing of sewing machine motors and their drive mechanisms.

Briefly, these and other objects of this invention are achieved by providing a pulley guard fabricated from wires that is secured on the end member of the motor and clutch housing in surrounding relationship to the driving pulley wheel and the drive pulley. The pulley guard is in the form of wires spaced apart to form an open basket type structure that will permit the passage of air, lint and small pieces of sewing debris, but will prevent accidental contact with or fouling of the pulley and pulley wheel.

The invention can be better understood in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a sewing machine having a pulley guard made in accordance with this invention; 7

FIG. 2 is an expanded perspective view illustrating the pulley guard of this invention and the end member of the motor and clutch housing adapted to seat in mating relationship with each other.

In FIG. 1, there is generally illustrated a sewing machine 10 that is driven by a pulley belt 11 from a drive mechanism 12 mounted beneath the work table 13. The drive mechanism 12 includes a constant rotating motor 14 that drives the spindle of the sewing machine 10 through the medium of a clutch mechanism 16. The clutch mechanism 16 is engaged by foot depression of the treadle 17 that causes the linkages 18 and 19 to shift that part of the clutch 16 that carries the belt driving mechanism into engagement with the rotating motor 14. Upon release of treadle 17, the belt carrying portion of the clutch mechanism 16 is disengaged from the motor 14 and en An end member 22 encloses one end of the motor and clutch housing 12. The end member 22 is provided with a journal box 23 to receive a rotating shaft (not shown) from the clutch 16. The drive shaft in turn carries a driving pulley (not shown) that, through engagement with pulley belt 11, is mechanically linked with the driven pulley 21. a

The linkage 19 is supported on fulcrum supports 24 to enable control over the operation of the clutch 16 when the foot treadle 17 is depressed and released.

The end member 22 is provided with a plurality of openings 26 and bosses 27. I

As is best illustrated in FIG. 2," the pulley' guard 30 of this invention is comprised of a rib-like configuration of medium gauge wires 31 that are held positioned by a framework of wires 34. In some instances, it may be desirable for the framework wires 34 to be of slightly heavier gauge wire than that of the ribbed members 31. The pulley guard 30 is designed in a configuration of a cage-like structure that generally conforms to the shape of the drive pulley and, with the exception of the upper portion thereof, encloses the drive pulley, thus permitting free rotation of the drive pulley and free travel of the driving belt 11 upwardly through the work table 13 to the driven pulley 21.

The transverse wire framework members 34 terminate and spindle of the sewing in C-shaped hook members 32 that are adapted to engage the aid member 22 "by passage through the slotted openings 26. When the hook members 32 are properly positioned within the slots 26, the guard 30 engages the upstanding bosses 27 on the end member 22 to secure the guard 30 from movement.

In the preferred embodiment of this invention, as illustrated in the drawings, the pulley guard 30 is secured to the end member 22 by first engaging the bottom hook members 32 in corresponding slots 26. The upper hook members 32 are then engaged with end member 22 by insetting them through corresponding slotted openings 26 directly below the bosses 27 by compressing the guard 30 to enable passage of the upper hook members 32 into the corresponding slots 26 of the end member 22. It will be understood that due to the natural resiliency of the wire framework, the frame can be compressed without causing permanent deformation of the guard 30, and that further, when such compressive forces are released, the wire framework 34 of the pulley guard 30 will cause the upper hook ends 32 to expand into seating relationship with the corresponding slotted openings 26.

While the gauge of the wire members is not particularly critical to this invention, it is to be understood that the wire from which the guard is made should be sufliciently heavy to withstand normal, impact, as by being bumped by the knees or by cleaning or repair equipment commonly operated in the vicinity of the machine. In addition, the spacing between the wires of the basket are not critical, but they should be sufiiciently large to allow for the free passage of any sewing debris that may fall from time to time into the pulley guard 30 from the work table 13.

When the pulley guard of this invention is properly installed upon the end member of the motor, the operator of the sewing machinne will be protected from accidental contact or fouling of the drive belt or pulley Wheel on the power transmission unit. In addition, the pulley guard of this invention will protect the pulley Wheel and drive belt from damage or interference by maintenance equipment operated in the proximity of the sewing table and other similar hazards.

From the above description of the drawings, it can be understood that the pulley guard of this invention will permit the free passage of air in and about the pulley wheel area as well as the passage of dust and cloth scraps, thus preventing the accumulation of such material within the pulley guard itself. By this means, cleaning of the pulley guard is greatly simplified and it need not be removed for cleaning. External application of vacuum devices commonly used for cleaning machinery will suflice for any cleaning that may be required. Since dust and sewing debris will not accumulate within the pulley guard, the potential fire hazard of such accumulations is thus eliminated. Furthermore, the pulley guard of this invention provides ample protection of the drive belt area so that the pulley and drive belt will not be contacted inadvertently by the machine operator. This factor eliminates risk of physical injury to the operator as well as insuring proper function of the motor and the pulley mechanism.

The pulley guard of this invention is also desirable in that minor adjustments may be made to the pulley wheel and the belt without removing the entire assembly due to the openings between the Wiresof the pulley guard.

Such open areas allow for the passage of air through and around the power transmission unit to dissipate motor heat. Also, as can be understood, the means of attachment are extremely simple and allow ready removal of the pulley guard when it is necessary to adjust the power transmission unit. V

The pulley guard of this invention is of simple manufacture and may be fabricated of readily available steel wire or other similar components spot welded or similarly attached according to common techniques at the points of intersection. The pulley guard may be coated with paint or other protective coverings. The economics possible through the use of the pulley guard of this invention are further enhanced by virtue of the fact that the device requires no independent attachment means for securing it to the electric motor and requires the application of no mechanical means of skill in attachment.

Although certain embodiments of this invention have: been shown in'the drawings and described in the speci-.

fication, it is to be understood .that the invention is not limited thereto, is capable of modification, and can be rearranged without departing from the spirit and scope of theinvention. I I claim:

1. A sewing machine mounted on the upper surface of" a work table and a drive mechanism comprising a motor housing having an end plate with slotted openings mounted on the under side of the work table, said sewing machine and drive mechanism being mechanically coupled in power-transmitting relationship by means of a drive belt, a drive pulley wheel mounted on the drive mechanism, a driven pulley wheel mounted on the sewing machine, and a pulley guard mounted on said end plate, surrounding, at least in part, the pulley wheel and drive belt, the pulley guard being fabricated from a plurality of resilient wires which wires are spaced apart to form an open basket-type structure in partial surrounding relationship to the driving pulley wheel that will protect the sewing machine operator from accidental contact with the pulley drive mechanism but will permit the passage of air, lint and small pieces of cloth debris, the pulley guard further carrying a plurality of hooks which hooks engage said slotted openings in said end plate of said motor' housing and are adapted to be seated or detached from the end plate by compression and release of the resilient wires.

References Cited UNITED STATES PATENTS 1,054,101 2/1913 Fessler. 1 1,196,469 8/1916 Merritt. 1,288,853 6/1917 Varley 74609 XR 1,600,208 9/1926 Amneus 74 609 2,096,621 10/1937 Skolfield 230-275 XR 2,961,591 11/1960 Frankel et al.

FOREIGN PATENTS 137,067 8/1952 Sweden.

RICHARD J. SCANLAN, JR., Primary Examiner. 7

US. 01. X.R. 74-611; 230-275 

